Light Imaging System for an Acoustic Imaging System

ABSTRACT

A light imaging system for an acoustic imaging system uses polarized light to illuminate a birefringent detector through a partially transparent mirror, a lens through which light reflected from the detector passes and a light imager views the mirror through a linear polarizer with the position of the light imager being adjusted to image the full detector and to minimize effects due to the non-linear behavior of the detector.

SUMMARY

It is a new result and unexpected discovery that the optimum angle condition of U.S. Pat. No. 6,049,411 can also be obtained using a partially transparent mirror between the birefringent detector and the light source and configuring together an angle between an imager and the mirror and a distance between the imager and the mirror.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows elements of the light imaging system. The light source 12 and the detector 14 can be interchanged.

DETAILED DESCRIPTION

A light imaging system using a partially transparent mirror between the birefringent detector and the light source and configuring together an angle between an imager and the mirror and a distance between the imager and the mirror obtains the conditions described in column 3 line 42 to column 4 line 16 and elsewhere in U.S. Pat. No. 6,049,411 which is incorporated in full herein by reference.

The new and unexpected light imaging system described and claimed here can replace the light imaging system of FIG. 2 in U.S. Pat. No. 6,049,411 which has been incorporated in full herein by reference.

The new light imaging system comprises:

a birefringent detector 14 in an acoustic imaging system,

a viewing plane of the detector;

a detector axis 24 orthogonal to the viewing plane;

a light source 12 providing incident light which illuminates the birefringent detector;

an incident light wavefront plane of the incident light;

a light axis 22 orthogonal to the wavefront plane;

a first linear or circular polarizer 16 between the light source and the detector;

a lens 15 through which incident light reflected by the detector passes;

a lens axis 25 of the lens;

a focal plane of the lens;

a partially transparent mirror 11 between the birefringent detector and the light source,

a reflecting plane of the mirror;

a mirror axis 21 orthogonal to the reflecting plane;

a light imager 13 viewing the mirror;

an imaging plane where an image is formed in the imager;

an imager axis 23 orthogonal to the imaging plane;

a second linear or circular polarizer 17 between the detector and the imager;

an imager angle between the imager axis and the mirror axis;

an imager distance between the imaging plane and the reflecting plane;

a lens distance between the lens focal plane and the imaging plane

a mirror angle between the mirror axis and the detector axis;

a light angle between the light axis and the detector axis;

a lens angle between the lens axis and the detector axis.

The imaging system also comprises configuration together of the lens distance, the imager angle, and the imager distance to provide sensitive and reliable images of the birefringent detector at the imager.

“Sensitive and reliable” herein means satisfying the conditions described in column 3 line 42 to column 4 line 16 and elsewhere in U.S. Pat. No. 6,049,411 which has been incorporated in full herein by reference. This especially includes minimizing effects due to the non-linear behavior of the detector.

The imaging system can also comprise configuration together of the lens distance, the imager angle, the imager distance, and the light angle to provide sensitive and reliable images of the detector at the image.

The imaging system can also comprise configuration together of the lens distance, the imager angle, the imager distance, the mirror angle, the light angle, and the lens angle to provide sensitive and reliable images of the detector at the image.

The birefringent detector and the acoustic imaging system are described in U.S. Pat. No. 6,049,411 which has been incorporated herein in full herein by reference.

Illuminating the birefringent detector is described in U.S. Pat. No. 6,049,411 which has been incorporated herein in full herein by reference.

Imaging light reflected by the birefringent detector is described in U.S. Pat. No. 6,049,411 which has been incorporated herein in full herein by reference.

When the axis of polarization of the second polarizer is orthogonal to the axis of polarization of the first polarizer, then black portions of an image formed by the imager correspond to portions of the detector which do not change the polarization of incident light. In this configuration less black portions of an image formed by the imager correspond to portions of the detector which have changed the polarization of incident light.

In an example, the birefringent detector 14 is a three inch by three inch model made by Santec Systems. A five inch by five inch Fresnel lens 15 with a seven inch focal length is just above the detector.

In the example, above the lens is a partially transparent mirror 11 with forty five degrees between the mirror axis 21 and the Detector axis 24. The mirror is large enough so that the imager can view the entire reflecting plane of the detector.

In the example, above the mirror is the light source 12 (LED Edge-Lit Panel, size 3.75″×3.75″, supplied by Knema Solid State Lighting) with the light axis 22 parallel to the detector axis 24. Just below the light source is a linear or circular polarizer 16 (AP42-007T from American Polarizers, Inc.).

In the example, the imager 13 (Model A311fc, from Basler Corporation) views the mirror. The lens distance, the imager distance, and the imager angle are adjusted together to view the full surface of the detector and to minimize effects due to the non-linear behavior of the detector.

Because of variations in the parts of the example configuration together of the lens distance, the imager distance, and the imager angle must be accomplished by experiment. 

What is claimed is:
 1. A light imaging system for an acoustic imaging system, the light imaging system comprising: a birefringent detector in an acoustic imaging system, a viewing plane of the detector; a detector axis orthogonal to the viewing plane; a light source providing incident light which illuminates the birefringent detector; an incident light wavefront plane of the incident light; a light axis orthogonal to the wavefront plane; a first polarizer between the light source and the detector; a lens through which incident light reflected by the detector passes; a lens axis of the lens; a focal plane of the lens; a partially transparent mirror between the birefringent detector and the light source, a reflecting plane of the mirror; a mirror axis orthogonal to the reflecting plane; a light imager viewing the mirror; an imaging plane where an image is formed in the imager; an imager axis orthogonal to the imaging plane; a second polarizer between the detector and the imager; an imager angle between the imager axis and the mirror axis; an imager distance between the imaging plane and the reflecting plane; a lens distance between the lens focal plane and the imaging plane a mirror angle between the mirror axis and the detector axis; a light angle between the light axis and the detector axis; a lens angle between the lens axis and the detector axis; and configuration together of the lens distance, the imager angle and the imager distance to provide sensitive and reliable images of the birefringent detector at the imager.
 2. The light imaging system of claim 1 also comprising configuration together of the lens distance, the imager angle, the imager distance, and the mirror angle to provide sensitive and reliable images of the detector at the image.
 3. The light imaging system of claim 1 also comprising configuration together of the lens distance, the imager angle, the imager distance, and the light angle to provide sensitive and reliable images of the detector at the image.
 4. The light imaging system of claim 1 also comprising configuration together of the lens distance, the imager angle, the imager distance, the mirror angle, and the light angle to provide sensitive and reliable images of the detector at the image.
 5. The light imaging system of claim 1 also comprising configuration together of the lens distance, the imager angle, the imager distance, the mirror angle, the light angle, and the lens angle to provide sensitive and reliable images of the detector at the image.
 6. A light imaging system for an acoustic imaging system, the light imaging system comprising: a birefringent detector in an acoustic imaging system, a viewing plane of the detector; a detector axis orthogonal to the viewing plane; a light source providing incident light which illuminates the birefringent detector; an incident light wavefront plane of the incident light; a light axis orthogonal to the wavefront plane; a first polarizer between the light source and the detector; a lens through which incident light reflected by the detector passes; a lens axis of the lens; a focal plane of the lens; a partially transparent mirror between the birefringent detector and the light source, a reflecting plane of the mirror; a mirror axis orthogonal to the reflecting plane; a light imager viewing the mirror; an imaging plane where an image is formed in the imager; an imager axis orthogonal to the imaging plane; a second polarizer between the detector and the imager; an imager angle between the imager axis and the mirror axis; an imager distance between the imaging plane and the reflecting plane; a lens distance between the lens focal plane and the imaging plane a mirror angle between the mirror axis and the detector axis; a light angle between the light axis and the detector axis; a lens angle between the lens axis and the detector axis; and configuration together of the lens distance, the imager angle, the imager distance, the mirror angle, the light angle, and the lens angle to provide sensitive and reliable images of the detector at the image. 